Conventionally, residential and commercial structures were insulated utilizing batts of fiberglass or other fiber formed insulating material. The fiberglass batting was applied in the cavity formed by vertical wall studs, an outer wall, a bottom sill and a top plate. Once the batt was fixed in position, a vapor barrier was mounted over the insulated wall, and drywall or other inner wall would then be mounted to the studs.
Another conventional method presently utilized to insulate walls includes the blowing or spraying of insulation material within a stud cavity. Typically, the blown insulation is an aggregate of insulation particles mixed with a wet adhesive or pure water to form spray or pneumatically applied "loose fill insulation". However, in order to insert the insulation in the wall cavity prior to installation of the inner wall, it was necessary to devise various methods for retaining the insulation in position prior to installation of the inner supporting skeletal wall.
U.S. Pat. No. 2,989,790 to Brown discloses a method of installing fibrous insulating material within a building wall by providing a perforate screen extending between the studs to form the "sixth wall" in combination with the outer wall, studs, plate and sill. The perforate screen does not extend the full height of the wall, such that it is necessary to install insulation at the bottom, permitting the loose fill insulation to dry and set, and then moving the screen sequentially upwardly until the entire wall cavity is filled with set loose fill insulation. There are several drawbacks associated with such a method. First, there is a substantial time delay in waiting for each section of insulation to dry and set prior to moving the perforate screen upwardly to install the next section of insulation. Second, water or other adhesive is necessary to "set" the insulation. The use of adhesive, including the step of mixing the adhesive with the insulation, is messy and time consuming. Third, a separate vapor barrier must then be installed over the interior surface of the set insulation, prior to installation of the inner wall.
U.S. Pat. No. 4,177,618 to Felter discloses a method for installing insulation in vertical walls of building between a permanent outer wall and a membrane on the inner side of the wall. The membrane is in the form of a sheet of transparent plastic and is temporarily supported as the loose insulation is installed behind the membrane. This support is provided by a shield plate, which covers the wall area into which the insulation is being delivered, and supports the membrane so that no outward sag of the membrane can occur. While the membrane provides a vapor barrier, the insulation is tapped and packed during delivery to attempt to prevent future settling of the insulation within the wall cavity. Once the insulation is installed and set, the shield plate is removed and drywall or other materials may be applied to form the inner wall. However, this method requires additional time delays and manpower to maintain the shield plate in position during installation of a insulation. In addition, the insulation is difficult to install at a uniform density by tapping or packing with the spray nozzle of the insulation delivery system.
Finally, U.S. Pat. No. 4,712,347 to Sperber discloses a method for installing insulation by attaching an air permeable netting material to the spaced wall studs to form the "sixth wall" or inner wall, during installation of the insulation. The netting is attached to the inner side of the studs from floor to ceiling, to form a retaining barrier for loose fill insulation which is inserted between the netting and the outer wall. A hole is cut in the netting, to receive a hose nozzle for delivery of the insulation which is blended with adhesive and water. The holes in the netting permit the air displaced by the deposited insulation to escape during the installation of the insulation. While the method of this patent decreases the time involved in installing the insulation, it is necessary to install a non air permeable vapor barrier over the insulated wall, prior to installation of an inner wall. Thus, any time savings are quickly reduced by subsequent necessary steps involved in installing the vapor barrier, as the vapor barrier should not be applied until all moisture has been totally evacuated from the stud cavity.